The present invention is in the field of linear ball bearings consisting of a cage with a plurality of ball guides distributed over its periphery, each guide having two straight races running parallel to the axis of the bearing and two semicircular races connecting the straight races, a cylindrical sleeve slipped over the cage, and a plurality of balls. In the region of the straight races in which the balls run back unloaded, the sleeve is provided with a longitudinal slit extending radially through the sleeve for each return race.
The linear ball bearings, also called drawn cup linear ball bearings having a thin-walled design, are known and include continuous longitudinal slits having a width which is smaller than the ball diameter. The balls are thus guided into the return zone by the edges of these longitudinal slits, which may continue into curved sections in which the balls are rerouted into the bearing zones as in DT-AS No. 1,266,574 which corresponds to U.S. Pat. No. 3,265,449. Also, there is the possibility of enlarging the sleeves in diameter at both axial ends in the region of the semicircular races, so that the turn-arounds are covered toward the outside as in DT-AS No. 1,262,69l which corresponds to U.S. Pat. No. 3,464,745. In these known embodiments the balls in each section of the race are always in contact with the sleeve, which leads to increased noise and wear, particularly in the regions in which the balls are not loaded. This is especially the case in the regions where the balls emerge from the loaded zone with the greatest speed.
One object of the present invention is to provide a ball bearing sleeve for use in bearings of the type initially described, in which the production of noise and wear is largely prevented.